This double-blind study of 20 patients with obsessive-compulsive disorder (OCD) tests the hypothesis that: 1) Intravenous pulse loading of clomipramine (150Mg Day 1, 200mg Day 2) will produce a larger decrease in symptoms of OCD than will identical oral doses; and 2) the larger the drop in core body temperature produced by the first dose of clomipramine, the more likely the patient's OCD symptoms will respond.